Dental health, prophylactic antibiotic measures and infective endocarditis: an analysis of the knowledge of susceptible patients.

A questionnaire was administered to 338 cardiac patients susceptible to infective endocarditis seen at the outpatient clinic or a cardiac ward. The questionnaire consisted of a series of questions on the educational, social, familial and professional background, the medical and dental history and the knowledge of the patient on prophylaxis of infective endocarditis. Univariate analysis (chi-square test) and stepwise discriminant analysis were used to evaluate the factors responsible for the presence or absence of an acceptable degree of awareness of infective endocarditis. More than half of the patients had no knowledge on prophylactic measures. The time since the diagnosis of heart disease, an edentulous state, written instructions received in the past on prophylaxis, the location of the follow-up, the level of education and previous prosthetic valve surgery were factors retained by discriminant analysis. A discriminant score was calculated for each patient and permitted classification in subgroups with a high, intermediate and low probability of presence of knowledge. This was simplified by classifying patients according to the number of risk factors. An answer to one of the six variables, selected by discriminant analysis, unfavorable for the presence of knowledge, was considered as a risk factor. Risk factor analysis must be considered as an important tool in the education of patients on the risk and prophylaxis of infective endocarditis.